/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.extensions.sql.impl.parser;



import com.bff.gaia.unified.sdk.extensions.sql.impl.UnifiedCalciteSchema;

import com.bff.gaia.unified.vendor.guava.com.google.common.collect.ImmutableList;

import org.apache.calcite.jdbc.CalcitePrepare;

import org.apache.calcite.jdbc.CalciteSchema;

import org.apache.calcite.sql.*;

import org.apache.calcite.sql.parser.SqlParserPos;



import java.util.List;



import static org.apache.calcite.util.Static.RESOURCE;



/**

 * Base class for parse trees of {@code DROP TABLE}, {@code DROP VIEW} and {@code DROP MATERIALIZED

 * VIEW} statements.

 */

abstract class SqlDropObject extends SqlDrop implements SqlExecutableStatement {

  protected final SqlIdentifier name;



  /** Creates a SqlDropObject. */

  SqlDropObject(SqlOperator operator, SqlParserPos pos, boolean ifExists, SqlIdentifier name) {

    super(operator, pos, ifExists);

    this.name = name;

  }



  @Override

  public List<SqlNode> getOperandList() {

    return ImmutableList.<SqlNode>of(name);

  }



  @Override

  public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {

    writer.keyword(getOperator().getName()); // "DROP TABLE" etc.

    if (ifExists) {

      writer.keyword("IF EXISTS");

    }

    name.unparse(writer, leftPrec, rightPrec);

  }



  @Override

  public void execute(CalcitePrepare.Context context) {

    final List<String> path = context.getDefaultSchemaPath();

    CalciteSchema schema = context.getRootSchema();

    for (String p : path) {

      schema = schema.getSubSchema(p, true);

    }

    final boolean existed;

    switch (getKind()) {

      case DROP_TABLE:

        if (schema.schema instanceof UnifiedCalciteSchema) {

          UnifiedCalciteSchema unifiedSchema = (UnifiedCalciteSchema) schema.schema;

          unifiedSchema.getTableProvider().dropTable(name.getSimple());

          existed = true;

        } else {

          existed = schema.removeTable(name.getSimple());

        }

        if (!existed && !ifExists) {

          throw SqlUtil.newContextException(

              name.getParserPosition(), RESOURCE.tableNotFound(name.getSimple()));

        }

        break;

      default:

        throw new AssertionError(getKind());

    }

  }

}



// End SqlDropObject.java